Air in vacuum-sealed bag phenomenon

[Chopstix]

This happens to me once in a while:

I would vacuum-seal something (say, cheese, meat, or nuts), stick it in the freezer, then after a month or so, find that there's air in it. I think the seal of the bag is still intact however because:
a) I re-examine all the sealed borders.
b) I am able to re-vacuum-seal the same bag, even by cutting and sealing the factory-sealed side of the bag just to test the integrity of the Foodsaver-sealed side. (My Foodsaver does not seal if it does not achieve a vacuum. So if there was even a pin hole in the bag due to snagging in the freezer or defective seal, the Foodsaver won't seal it and the indicator light does not go on.)

Btw, I only use the prescribed Foodsaver plastic bags.

My question: Can the sealed food possibly be generating gas over time?

Please note that this phenomenon happens only once in a while. Most of the time, my sealed stuff stay intact forever.

TIA!

 

[pacanis]

That happens to me once in a while, too. Both with my FS and with my handi-vac, freezer and fridge.

 

[Andy M.]

There can be a tiny leak in a seam or somewhere in the bag that's so small it doesn't prevent a vacuum long enough to make a seal. then over time, air leaks in.

I doubt any foods are generating their own gas in the freezer.

 

[Chopstix]

You're most probably right Andy. Sometimes there's so much air in the problematic bag that it can't possibly have come from the food. Thanks Andy and Pacanis.